evaluation the effect of water stress and foliar application of fe nanoparticles on yield, yield components and oil percentage of safflower (carthamus tinctorious l.)

to study the impact of iron nanoparticles foliar application on mitigating the effects of drought stress on yield, yield components and oil percentage of goldasht spring safflower cultivar, an experiment was carried out in 2012 in the agricultural research farm station of islamic azad university, roudehen branch as split plot in a completely randomized blocks design with three replications. in this experiment, the major factor of drought stress treatment included four levels (optimum irrigation, stopping the irrigation at flowering stage, stopping the irrigation at seed formation stage and stopping the irrigation at two stages of flowering and seed formation). the minor treatment factor consisted of fe nanoparticles foliar application at four levels (non-applying the foliar, foliar application at flowering stage, foliar application at seed formation stage and foliar application at two stages of flowering and seed formation). after data analysis by sas software, the parameters including analyses of variance and means were compared using the duncan's multiple range test at probability level of 5%. the results showed that the effects of drought stress and fe nanoparticles were significant at probability level of 1% on traits such as the number of boll per branch, number of seeds per boll, the thousand seed weight and yield at probability level of 1%. among the levels of drought stress, the highest yield and yield components losses were seen for most of the traits and between the levels of 2 times drought stress. the maximum yield and yield components rates related to the control treatment (optimum irrigation). also, among the levels of fe nanoparticles, the use of nanoparticles produced the highest rates of yield and yield components in two stages of flowering and granulation. also, the foliar application at flowering stage was better than seed formation. meanwhile, the control treatment had the lowest yield and yield components. finally, the interactions of fe nanoparticles and different levels of drought stress at 1% probability level had significant impacts on traits, including boll number per branch, number of seeds per boll, the thousand seed weight and the yield. at the end of the experiment, the 2 times stress had the highest yield and yield components losses, and 2 times of using nanoparticles had the highest rates of yield and yield components. thus, the adverse effects of drought stress can be reduced in this area and similar areas by application of fe nanoparticles.